Issue 11875: Keep OrderedDict's __reduce__ from temporarily mutating the object.

diff --cc Misc/NEWS
index c1fb1649d9de832080604bbdfef2a1f29658ef57,1885fb73cf9bb1258b89c870804467d942a93f24..fe6ba0194b08dba9569d69f0416fb69d4eb3ac64
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -60,14 -60,11 +60,17 @@@ Core and Builtin
  Library
  -------
  
 +- Issue #11768: The signal handler of the signal module only calls
 +  Py_AddPendingCall() for the first signal to fix a deadlock on reentrant or
 +  parallel calls. PyErr_SetInterrupt() writes also into the wake up file.
 +
 +- Issue #11492: fix several issues with header folding in the email package.
 +
  - Issue #11852: Add missing imports and update tests.
  
+ - Issue #11875: collections.OrderedDict's __reduce__ was temporarily
+   mutating the object instead of just working on a copy.
+ 
  - Issue #11467: Fix urlparse behavior when handling urls which contains scheme
    specific part only digits. Patch by Santoso Wijaya.